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Researchers have, for the first time, identified the sufficient and necessary conditions that the low-energy limit of quantum gravity theories must satisfy to preserve the main features of the Unruh effect.

A KAIST team has designed a novel strategy for synthesizing single-crystalline graphene quantum dots, which emit stable blue light. The research team confirmed that a display made of their synthesized graphene quantum dots successfully emitted blue light with stable electric pressure, reportedly resolving the long-standing challenges of blue light emission in manufactured displays. The study, led by Professor O Ok Park in the Department of Chemical and Biological Engineering, was featured online in Nano Letters on July 5.

Graphene has gained increased attention as a next-generation material for its heat and electrical conductivity as well as its transparency. However, single and multi-layered graphene have characteristics of a conductor so that it is difficult to apply into semiconductor. Only when downsized to the nanoscale, semiconductor’s distinct feature of bandgap will be exhibited to emit the light in the graphene. This illuminating featuring of dot is referred to as a graphene quantum dot.

Conventionally, single-crystalline graphene has been fabricated by chemical vapor deposition (CVD) on copper or nickel thin films, or by peeling graphite physically and chemically. However, graphene made via chemical vapor deposition is mainly used for large-surface transparent electrodes. Meanwhile, graphene made by chemical and physical peeling carries uneven size defects.

China has declared its ambition to dominate the technology sector from 5G and artificial intelligence to robotics and quantum computing. Joining the infrastructure firms on this year’s list are technology firms such as Alibaba, http://JD.com/, Tencent, Xiaomi, and BOE. Huawei was not included as it is a private entity.

China’s ambition to dominate the technology sector from 5G and artificial intelligence to robotics and quantum computing is bearing fruit.

When you pop a tray of water into the freezer, you get ice cubes. Now, researchers from the University of Colorado Boulder and the University of Toronto have achieved a similar transition using clouds of ultracold atoms.

In a study that will appear August 2 in the journal Science Advances, the team discovered that it could nudge these quantum materials to undergo transitions between “dynamical phases”—essentially, jumping between two states in which the atoms behave in completely different ways.

“This happens abruptly, and it resembles the phase transitions we see in systems like water becoming ice,” said study co-author Ana Maria Rey. “But unlike that tray of ice cubes in the freezer, these phases don’t exist in equilibrium. Instead, atoms are constantly shifting and evolving over time.”

Quantum sensors based on nitrogen-vacancy (NV) centers in diamond are a promising detection mode for nuclear magnetic resonance spectroscopy due to their micron-scale detection volume and noninductive-based sample detection requirements. A challenge that exists is to sufficiently realize high spectral resolution coupled with concentration sensitivity for multidimensional NMR analysis of picolitre sample volumes. In a new report now on Science Advances, Janis Smits and an interdisciplinary research team in the departments of High Technology Materials, Physics and Astronomy in the U.S. and Latvia addressed the challenge by spatially separating the polarization and detection phases of the experiment in a microfluidic platform.

They realized a spectral resolution of 0.65±0.05 Hz, an order-of-magnitude improvement compared with previous diamond NMR studies. Using the platform, they performed 2-D correlation spectroscopy of liquid analytes with an effective detection volume of ~40 picoliters. The research team used diamond quantum sensors as in-line microfluidic NMR detectors in a major step forward for applications in mass-limited chemical analysis and single-cell biology.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful and well-established technique for compositional, structural and functional analysis in a variety of scientific disciplines. In conventional NMR spectrometry the signal-to-noise ratio (SNR) is strongly dependent on the external field strength (B₀). As the spectral resolution increased, the B₀ increased as well, motivating the development of increasingly large and expensive superconducting magnets for improved resolution and SNR, resulting in a two-fold increase in field strength within the past 25 years.

A number of NASA scientists are currently researching the feasibility of warp drive (and EMdrive and a number of other modes of faster than light travel); however, most scientists think that such forms of space travel simply aren’t viable, thanks to the fundamental physics of our universe.

“Routine travel among the stars is impossible without new discoveries regarding the fabric of space and time, or capability to manipulate it for our needs,” says Neil deGrasse Tyson, the “Cosmos famous” astrophysicist at the American Museum of Natural History, said “By my read, the idea of a functioning warp drive remains far-fetched, but the real take-away is that people are thinking about it — reminding us all that the urge to explore continues to run deep in our species.”

There have been hints the past few years that NASA may be on the path to discovering warp bubbles that could make the local universe accessible for human exploration. NASA scientists may be close announcing they may have broken the speed of light. According to state-of-the art theory, a warp drive could cut the travel time between stars from tens of thousands of years to weeks or months.

This week’s podcast features an interview with Ray LaPierre, who heads up the department of engineering physics at McMaster University in Canada. Ray talks to fellow Canadian Hamish Johnston about his research in semiconductor nanowires, in particular for use in photonics and quantum computers, and also shares his experiences of working at JDS Uniphase during the telecoms boom.

Physics World’s Anna Demming also joins the podcast to describe a flurry of new results in the emerging field of twistronics – where two layers of graphene are stacked on top of each other but twisted at a slight angle to each other. The discovery last year that bilayer graphene can become a superconductor if the two graphene layers are twisted at the so-called magic angle of 1.1º won Physics World’s 2018 Breakthrough of the Year, and since then the race has been on to investigate other angle-dependent properties of twisted bilayer graphene. Anna describes how different research teams are now trying to work out what causes these intriguing effects.

We also talk to industry editor Margaret Harris about the importance of technology and engineering for scientific progress. Margaret shares her own “light-bulb” moment, when she realized that new laser technology could have saved hours of experimental time during her PhD, and also highlights several articles in the latest Physics World Focus on Instruments and Vacuum that highlight how breakthrough scientific discoveries rely on developments in the enabling technologies – including the first images of a black hole that were revealed in April.

The phenomenon known as “tunneling” is one of the best-known predictions of quantum physics, because it so dramatically confounds our classical intuition for how objects ought to behave. If you create a narrow region of space that a particle would have to have a relatively high energy to enter, classical reasoning tells us that low-energy particles heading toward that region should reflect off the boundary with 100% probability. Instead, there is a tiny chance of finding those particles on the far side of the region, with no loss of energy. It’s as if they simply evaded the “barrier” region by making a “tunnel” through it.

It’s very important to note that this phenomenon is absolutely and unquestionably real, demonstrated in countless ways. The most dramatic of these is sunlight— the Sun wouldn’t be able to fuse hydrogen into helium without quantum tunneling— but it’s also got more down-to-earth technological applications. Tunneling serves as the basis for Scanning Tunneling Microscopy, which uses the tunneling of electrons across a tiny gap between a sharp tip and a surface to produce maps of that surface that can readily resolve single atoms. It’s also essential for the Josephson effect, which is the basis of superconducting detectors of magnetic fields and some of the superconducting systems proposed for quantum computing.

So, there is absolutely no debate among physicists about whether quantum tunneling is a thing that happens. Physicists get a bit twitchy without something to argue over, though, and you don’t have to dig into tunneling (heh) very far to find a disputed question, namely “How long does quantum tunneling take?”

O.o!

A team of scientists recently determined certain quantum particles can regenerate after they’ve decayed. This has grand implications for the future of humanity, quantum computing, and intergalactic graffiti.

Theoretical physicists from the Technical University of Munich and the Max Planck Institute conducted simulation experiments to determine that certain quasiparticles are essentially immortal. Per the second law of thermodynamics nothing lasts forever, but these quantum particle fields can reassemble themselves after decaying – just like the phoenix from Greek mythology.

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